Résumé : Milgram’s classical studies famously suggested a widespread willingness to obey authority, even to the point of inflicting harm. Important situational factors supporting obedience, such as proximity with the victim, have been established. Relatively little work has focused on how coercion affects individual cognition, or on identifying the cognitive factors that underlie inter-individual differences in the tendency to yield to coercion. Here, we used fMRI to investigate the neural systems associated with changes in volitional processes associated with sense of agency and sense of responsibility under coercion. Participants either freely chose, or were instructed by the experimenter, to give mildly painful electric shocks to another participant, or to refrain from doing so. We have previously shown that coercion reduces temporal binding, which has been proposed as an implicit proxy measure of sense of agency. We tested how reduced agency under coercion related to differences in neural activity between free choice and coercion. In contrast to previous studies and to participants performing the task outside the MRI scanner, on average there was no effect of coercion on agency for participants in the scanner. However, greater activity in the medial frontal gyrus was reliably associated with greater agency under coercion. A similar association was found using explicit responsibility ratings. Our findings suggest that medial frontal processes, perhaps related to volition during action planning and execution, may help to preserve a sense of accountability under coercion. Further, participants who administered more shocks under free choice showed reduced activity during free choice trials in brain areas associated with social cognition. Possibly, this might reflect participants cognitively distancing themselves from the recipient of the shocks under free choice, whereas this was not observed under coercion.